100 research outputs found
A Survey on Cellular-connected UAVs: Design Challenges, Enabling 5G/B5G Innovations, and Experimental Advancements
As an emerging field of aerial robotics, Unmanned Aerial Vehicles (UAVs) have
gained significant research interest within the wireless networking research
community. As soon as national legislations allow UAVs to fly autonomously, we
will see swarms of UAV populating the sky of our smart cities to accomplish
different missions: parcel delivery, infrastructure monitoring, event filming,
surveillance, tracking, etc. The UAV ecosystem can benefit from existing 5G/B5G
cellular networks, which can be exploited in different ways to enhance UAV
communications. Because of the inherent characteristics of UAV pertaining to
flexible mobility in 3D space, autonomous operation and intelligent placement,
these smart devices cater to wide range of wireless applications and use cases.
This work aims at presenting an in-depth exploration of integration synergies
between 5G/B5G cellular systems and UAV technology, where the UAV is integrated
as a new aerial User Equipment (UE) to existing cellular networks. In this
integration, the UAVs perform the role of flying users within cellular
coverage, thus they are termed as cellular-connected UAVs (a.k.a. UAV-UE,
drone-UE, 5G-connected drone, or aerial user). The main focus of this work is
to present an extensive study of integration challenges along with key 5G/B5G
technological innovations and ongoing efforts in design prototyping and field
trials corroborating cellular-connected UAVs. This study highlights recent
progress updates with respect to 3GPP standardization and emphasizes
socio-economic concerns that must be accounted before successful adoption of
this promising technology. Various open problems paving the path to future
research opportunities are also discussed.Comment: 30 pages, 18 figures, 9 tables, 102 references, journal submissio
Coexistence of UAVs and Terrestrial Users in Millimeter-Wave Urban Networks
5G millimeter-wave (mmWave) cellular networks are in the early phase of
commercial deployments and present a unique opportunity for robust,
high-data-rate communication to unmanned aerial vehicles (UAVs). A fundamental
question is whether and how mmWave networks designed for terrestrial users
should be modified to serve UAVs. The paper invokes realistic cell layouts,
antenna patterns, and channel models trained from extensive ray tracing data to
assess the performance of various network alternatives. Importantly, the study
considers the addition of dedicated uptilted rooftop-mounted cells for aerial
coverage, as well as novel spectrum sharing modes between terrestrial and
aerial network operators. The effect of power control and of multiuser
multiple-input multiple-output are also studied
A Comprehensive Overview on 5G-and-Beyond Networks with UAVs: From Communications to Sensing and Intelligence
Due to the advancements in cellular technologies and the dense deployment of
cellular infrastructure, integrating unmanned aerial vehicles (UAVs) into the
fifth-generation (5G) and beyond cellular networks is a promising solution to
achieve safe UAV operation as well as enabling diversified applications with
mission-specific payload data delivery. In particular, 5G networks need to
support three typical usage scenarios, namely, enhanced mobile broadband
(eMBB), ultra-reliable low-latency communications (URLLC), and massive
machine-type communications (mMTC). On the one hand, UAVs can be leveraged as
cost-effective aerial platforms to provide ground users with enhanced
communication services by exploiting their high cruising altitude and
controllable maneuverability in three-dimensional (3D) space. On the other
hand, providing such communication services simultaneously for both UAV and
ground users poses new challenges due to the need for ubiquitous 3D signal
coverage as well as the strong air-ground network interference. Besides the
requirement of high-performance wireless communications, the ability to support
effective and efficient sensing as well as network intelligence is also
essential for 5G-and-beyond 3D heterogeneous wireless networks with coexisting
aerial and ground users. In this paper, we provide a comprehensive overview of
the latest research efforts on integrating UAVs into cellular networks, with an
emphasis on how to exploit advanced techniques (e.g., intelligent reflecting
surface, short packet transmission, energy harvesting, joint communication and
radar sensing, and edge intelligence) to meet the diversified service
requirements of next-generation wireless systems. Moreover, we highlight
important directions for further investigation in future work.Comment: Accepted by IEEE JSA
UAV Communications in Integrated Terrestrial and Non-terrestrial Networks
With growing interest in integrating terrestrial networks (TNs) and
non-terrestrial networks (NTNs) to connect the unconnected, a key question is
whether this new paradigm could also be opportunistically exploited to augment
service in urban areas. We assess this possibility in the context of an
integrated TN-NTN, comprising a ground cellular deployment paired with a Low
Earth Orbit (LEO) satellite constellation, providing sub-6 GHz connectivity to
an urban area populated by ground users (GUEs) and uncrewed aerial vehicles
(UAVs). Our study reveals that offloading UAV traffic to the NTN segment
drastically reduces the downlink outage of UAVs from 70% to nearly zero, also
boosting their uplink signal quality as long as the LEO satellite constellation
is sufficiently dense to guarantee a minimum elevation angle. Offloading UAVs
to the NTN also benefits coexisting GUEs, preventing uplink outages of around
12% that GUEs would otherwise incur. Despite the limited bandwidth available
below 6 GHz, NTN-offloaded UAVs meet command and control rate requirements even
across an area the size of Barcelona with as many as one active UAV per cell.
Smaller UAV populations yield proportionally higher rates, potentially enabling
aerial broadband applications
Survey on 6G Frontiers: Trends, Applications, Requirements, Technologies and Future Research
Emerging applications such as Internet of Everything, Holographic Telepresence, collaborative robots, and space and deep-sea tourism are already highlighting the limitations of existing fifth-generation (5G) mobile networks. These limitations are in terms of data-rate, latency, reliability, availability, processing, connection density and global coverage, spanning over ground, underwater and space. The sixth-generation (6G) of mobile networks are expected to burgeon in the coming decade to address these limitations. The development of 6G vision, applications, technologies and standards has already become a popular research theme in academia and the industry. In this paper, we provide a comprehensive survey of the current developments towards 6G. We highlight the societal and technological trends that initiate the drive towards 6G. Emerging applications to realize the demands raised by 6G driving trends are discussed subsequently. We also elaborate the requirements that are necessary to realize the 6G applications. Then we present the key enabling technologies in detail. We also outline current research projects and activities including standardization efforts towards the development of 6G. Finally, we summarize lessons learned from state-of-the-art research and discuss technical challenges that would shed a new light on future research directions towards 6G
Millimeter-Wave UAV Coveragein Urban Environments
With growing interest in mmWave connectivity for UAVs, a basic question is
whether networks intended for terrestrial users can provide sufficient aerial
coverage as well. To assess this possibility, the paper proposes a novel
evaluation methodology using generative models trained on detailed ray tracing
data. These models capture complex propagation characteristics and can be
readily combined with antenna and beamforming assumptions. Extensive simulation
using these models indicate that standard (street-level and downtilted) base
stations at typical microcellular densities can indeed provide satisfactory UAV
coverage. Interestingly, the coverage is possible via a conjunction of antenna
sidelobes and strong reflections. With sparser deployments, the coverage is
only guaranteed at progressively higher altitudes. Additional dedicated
(rooftop-mounted and uptilted) base stations strengthen the coverage provided
that their density is comparable to that of the standard deployment, and would
be instrumental for sparse deployments of the latter
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